Sled ride question?

Question

To give a 16 kg child a ride, two teenagers pull on a 3.4 kg sled with ropes. Both teenagers pull with a force of F = 65 N at an angle of 35° relative to the forward direction, which is the direction of motion. In addition, the snow exerts a retarding force on the sled that points opposite to the direction of motion, and has a magnitude of 57 N. Find the size of the acceleration of the sled and child.

Answer 1

F (of kids pulling sled) = 65 * cos (35)  I am assuming that they pull with a COMBINED force of 65.  If they EACH do so, then multiply this bt 2...OK?

F = 53.2 N

Retarding force = 57 N  OK, it must be that EACH kid pulls with 65 N..

so F = 106.4 N from two pullers

NET FORCE = 106.4-57=49.4 N

F(net) = mass * accel, so since mass=16+3.4 = 19.4 kg...

a= 49.4/19.4 = 2.55 m/sec^2

-Fred